From mboxrd@z Thu Jan  1 00:00:00 1970
X-Spam-Checker-Version: SpamAssassin 3.4.4 (2020-01-24) on polar.synack.me
X-Spam-Level: 
X-Spam-Status: No, score=-1.9 required=5.0 tests=BAYES_00
	autolearn=unavailable autolearn_force=no version=3.4.4
Path: 
 eternal-september.org!reader01.eternal-september.org!reader02.eternal-september.org!.POSTED!not-for-mail
From: Paul Rubin <no.email@nospam.invalid>
Newsgroups: comp.lang.ada
Subject: Re: SI Units Checked and Unchecked
Date: Sat, 11 Aug 2018 12:57:33 -0700
Organization: A noiseless patient Spider
Message-ID: <877ekw1xsi.fsf@nightsong.com>
References: <9381f30a-a957-4477-b037-b2d60041e83e@googlegroups.com>
	<d628e94f-7ea0-4616-96a9-eb28ff6c9d6e@googlegroups.com>
	<pkhhqo$4d8$1@gioia.aioe.org>
	<aea11f39-b169-4490-a4c7-1306ecbe8e2d@googlegroups.com>
	<pkhnur$fp9$1@gioia.aioe.org>
	<60ddd5ae-57e1-45e8-929c-302fabaa24ef@googlegroups.com>
	<pki5fj$183p$1@gioia.aioe.org>
	<fc75437f-45d6-495e-8dbd-1f9aaa2014bc@googlegroups.com>
	<pkjcao$srd$1@gioia.aioe.org>
	<96424a63-d811-4ade-88db-258f3febe60a@googlegroups.com>
	<pkk8oa$feh$1@gioia.aioe.org>
	<99af08dd-39fb-4c1e-a247-eef9680a2abd@googlegroups.com>
	<pkkiaj$1059$1@gioia.aioe.org> <87k1oxfr9v.fsf@nightsong.com>
	<pklt7n$t7v$1@gioia.aioe.org>
Mime-Version: 1.0
Content-Type: text/plain
Injection-Info: reader02.eternal-september.org;
 posting-host="f31cea886a7d49865f708e61376b3999";
	logging-data="30231"; mail-complaints-to="abuse@eternal-september.org";
	posting-account="U2FsdGVkX19N9nkYpZPvJ2HgdTBYqhfb"
User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/25.3 (gnu/linux)
Cancel-Lock: sha1:95uDye27XnHT2Y18vd84BAQKywA=
	sha1:7/K2jh8cUYjIKOjcSADdsoj9I/I=
Xref: reader02.eternal-september.org comp.lang.ada:54144
Date: 2018-08-11T12:57:33-07:00
List-Id: <comp.lang.ada>

"Dmitry A. Kazakov" <mailbox@dmitry-kazakov.de> writes:
>>> No language change can make dynamic cases static.
>> I think the idea is to allow constraints on generic instantiation
>> precise enough to use them for unit checking.
> Dynamic is not static.

Well the idea is to check the constraints statically.  Obviously in
cases where values can be introduced at runtime, there must be a way to
connect them up with units, through protected methods or whatever.
Once they are in the system, the types track them.

I don't understand why there is even a desire in a scientific-style
program to track quantities in more than one dimensionally equivalent
unit (e.g. liters vs gallons).  Just convert everything to a uniform set
of units (probably SI) when they come into the system, and then do all
internal calculations with that unit set.